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Old 09-05-2007, 04:12 PM
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help me troubleshoot some wiring?

Hi guys, I need your help. I've got a '69 RS with a 350, HEI coil, and some creative wiring from a previous owner. Its been in storage for a long time and its time to bring this puppy back to life. Last time I started it up, it wouldn't shut off. There was an ignition cutoff toggle switch hidden under the dash, I flipped it and nothing happened, flipped it back and still nothing, engine still running with ignition switch in the off position. I ripped the toggle switch out in frustration, and the engine shut off. I started it back up and it started fine, but wouldn't shut off again and I had no other annoying switches to rip out, so I pulled the little hot lead off the distributor and it cut off. I haven't started it again since. It seems clear to me that theres probably a short somewhere pretty basic, I have a multimeter so I can check stuff on it...can you tell me how to find the problem?

I'm sure its relatively simple, just put a lead on the hot wire & the other lead to the terminal on the distributor, then it should read one thing with the ignition switch off and something else with the switch on. But what does it want to read? Do I check voltage, ohms, continuity, tire pressure ? Just kidden about tire pressure, but seriously, how do I find the problem? And then once I find it & fix it, how do I make sure its fixed without starting up an engine that I can't shut off again? I figured to start I should splice the 2 wires together that used to be connected to that cut-off switch so that its a complete circuit...yes?

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Old 09-05-2007, 06:30 PM
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Try this

http://www.edelbrock.com/tech/tech_s...g/hei_con.html
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Old 09-05-2007, 06:42 PM
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Ok, from that picture, its the battery one that I had to pull off to kill it. So, if i just check for continuity between the battery tab & the ground tab, the circuit should be open when the ignition is off & complete when the ignition is on, right?
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Old 09-05-2007, 06:43 PM
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The battery power to the HEI needs to be on a feed that runs to the fuse panel, on a circuit that is controlled specifically by the ignition switch, on when the ignition switch is on and off when the switch is off. I know that sounds simple enough, but more times than not, laziness sets in, and someone tries to shortcut running a feed all the way back to the fuse panel and will tie it into the nearest available power source and then wonder why stuff doesn’t work right. Then wire in a cutoff switch to fix the problem they just created.

It sounds like the power feed to the distributor is currently connected to a power source that may be getting feedback from the alternator or is on a power feed that is not shutdown by the ignition switch. I would start at the distributor and trace the power wire back to see where its connected. But, not knowing what the previous owner may have done, I would run a completely new power feed to the distributor from the fuse panel, from a circuit that is controlled by the igintion switch,and eliminate the problem you are having. And remove the cutoff switch and its wiring, not needed if the distributor is wired correctly.
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Old 09-05-2007, 07:23 PM
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Electronic Ignition

I have a 69 Camaro that I added a MSD electronic ignition. When first started after installing new system, the car continued to run after the key was shut off. I read in the troubleshooting guide that enough electrical current runs through the external voltage regulator to keep the motor running after the key is shut down. I installed the diode included with the system to the brown wire on the voltage regulator, and the problem was solved. Don't know if you have an electronic ignititon system, but might solve your problem.
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Old 09-06-2007, 03:23 PM
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Quote:
Originally Posted by Hoptup32
The battery power to the HEI needs to be on a feed that runs to the fuse panel, on a circuit that is controlled specifically by the ignition switch, on when the ignition switch is on and off when the switch is off. I know that sounds simple enough, but more times than not, laziness sets in, and someone tries to shortcut running a feed all the way back to the fuse panel and will tie it into the nearest available power source and then wonder why stuff doesn’t work right. Then wire in a cutoff switch to fix the problem they just created.

It sounds like the power feed to the distributor is currently connected to a power source that may be getting feedback from the alternator or is on a power feed that is not shutdown by the ignition switch. I would start at the distributor and trace the power wire back to see where its connected. But, not knowing what the previous owner may have done, I would run a completely new power feed to the distributor from the fuse panel, from a circuit that is controlled by the igintion switch,and eliminate the problem you are having. And remove the cutoff switch and its wiring, not needed if the distributor is wired correctly.
So, to start with, it sounds like I should reconnect the wire that had that cutoff switch in it, and use the volt meter see if it has 12V with the ignition switch on, and 0V with it off, right? Then, if it turns out that its 12V even when ignition is off, I should cut that wire out, find a circuit on the fuse block that has 12V with ignition on and 0V with ignition off, and wire it into there?
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Old 09-06-2007, 05:31 PM
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Help me

Yes, just make sure the circuit you use can carry the current the distributer needs. I imagine it should be protected by at least a 10 amp fuse. I'll try to look into that for you. You could probably just Google HEI ignition and find out exactly what you need to know for current capacity.
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Old 09-06-2007, 05:45 PM
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Help me

Ok, I checked out a wiring diagram for a 1985 Z28, sorry my diagrams don't go back to 1969. The pink, 12 volt wire to the coil comes directly from the ignition switch. The only protection in the circuit is a fusible link at the starter solenoid that feeds the ignition switch. You should use that type of circuit so you'll get full battery voltage to the coil. because it's just 2 wires, one on either side of the ignition switch, there's less chance of a voltage loss to the coil in the circuit.
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Old 09-06-2007, 06:51 PM
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Ok, I'll test it tonight when I get home, and then start tryin' to figure out how to get into my steering column to make it right. Thanks for the help!
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Old 09-06-2007, 07:31 PM
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help me

The problem may not be in the switch, so check the wiring where it comes out at the bottom of the steering column first.
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Old 09-06-2007, 08:46 PM
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In 1969 the original ignition system was the old points style distributor and coil, not the HEI ignition that is installed now. The original pink wire from the ignition switch to the original coil changed to a white/orange resistor wire to drop the coil voltage to 9v. The HEI needs to see a full 12v to operate correctly. So if you utilize the pink iginition switch wire, make sure the resistor wire has been removed or bypassed so you have the required 12v to the HEI battery terminal.
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Old 09-07-2007, 12:26 AM
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I spliced a jumper in to replace the cut off switch that was there and tested it, looks like its working correctly now, but doesn't get quite all the juice. The battery is at 12.4V, with the ignition switch on the distributor sees 11.82V. With it off, sometimes it sees -0.0 and sometimes it sees up to 12 mV. Any idea where that 12 mV may be coming from or whether or not it matters?

Is 11.82 enough for the HEI? Keep in mind, I'm doing these tests without the engine running so the system isn't at full voltage due to the alternator not spinning...

Everything looked ready to try starting her up, she cranks fine but won't fire. I put a fuel stabilizer in when I parked it about a year & a half ago, so hopefully it hasn't turned to varnish just yet, but even with starter fluid in the carb it wouldn't fire so I'm thinking I still have a spark issue. Whats the next step, pull a plug wire & crank it to see if its sparking? Pull plugs to see if they got fouled by the mystery oil I put in the cylinders to preserve the rings? Consider the electrical problem solved and create a new thread in the engine forum?
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Old 09-07-2007, 05:56 AM
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help me

Hoptup32 is the resistance built right into the wire, or is there a separate resistor? Bill-E Bob, did you bypass or eliminate the wire or resistor?
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Old 09-07-2007, 10:53 AM
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I didn't see a resistor like described, I hadn't read that post until I already came back upstairs so I didn't know I should be looking for it. All I bypassed was the toggle switch they were using as a kill. The voltage is higher than 9V though so I'd imagine that whoever installed the HEI originally bypassed the resistor at that time. I would've called the wire red instead of pink, so unless the factory used a very dark pink its been replaced with a red one at some point.
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Old 09-07-2007, 11:29 AM
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Help me

I'm not sure what the wire color was in 1969. In 1985 and many other years it was pink, but again, I don't know about 69. It sounds like there are other problems besides that single wire, although you're probably on the right track bypassing the toggle switch.
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